text: Although the Vaiśeṣika system developed independently from the Nyāya philosophy of Hinduism, the two became similar and are often studied together. In its classical form, however, the Vaiśeṣika school differed from the Nyāya in one crucial respect: where Nyāya accepted four sources of valid knowledge, the Vaiśeṣika accepted only two.
  The epistemology of Vaiśeṣika school of Hinduism accepted only two reliable means to knowledge – perception and inference.
  Vaisheshika espouses a form of atomism, that the reality is composed of five substances (examples are earth, water, air, fire, and space). Each of these five are of two types, explains Ganeri: paramāṇu and composite. A paramāṇu is that which is indestructible, indivisible, and has a special kind of dimension, called "small" (aṇu). A composite is that which is divisible into paramāṇu. Whatever human beings perceive is composite, and even the smallest perceptible thing, namely, a fleck of dust, has parts, which are therefore invisible. The Vaiśeṣikas visualized the smallest composite thing as a "triad" (tryaṇuka) with three parts, each part with a "dyad" (dyaṇuka). Vaiśeṣikas believed that a dyad has two parts, each of which is an atom. Size, form, truths and everything that human beings experience as a whole is a function of parmanus, their number and their spatial arrangements.
  Parama means "most distant, remotest, extreme, last" and aṇu means "atom, very small particle", hence paramāṇu is essentially "the most distant or last small (i.e. smallest) particle".
  Vaiśeṣika postulated that what one experiences is derived from dravya (substance: a function of atoms, their number and their spatial arrangements), guna (quality), karma (activity), samanya (commonness), vishesha (particularity) and samavaya (inherence, inseparable connectedness of everything).
  The followers of this philosophy are mostly Shaivas. Acharya Haribhadra Suri, in his work Ṣaḍdarśanasamuccaya describes the followers of Vaiśeṣika as worshippers of Pashupati or Shiva.